Give Animals Civil Rights

As you may know the human race has a history with discriminating, depriving of rights, and treating one another as if they are a lesser form. But who are we to decide what a lesser form is? When Africans were enslaved, some reasons why Europeans believed it was ok was because they thought of Africans barbaric,uneducated beings. They referred to them as animals. That wasn't the case though,because Africans appearances were different they were treated like lesser forms of life. This all changed when the 13th Amendment was made but why is this amendment only affecting humans, it never specified what species this would apply to so shouldn't it apply to all species. How would we know if animals want to become pets. We don't, that's why we give them civil rights, so they can decided for themself